Method of and apparatus for use in the manufacture of pipes, tubes, and the like



July 1924. 3,499,719

L. BILL METHOD OF AND APPARATUS FOR USE IN THE MANUFACTURE OF PIPES,TUBES, AND THE LIKE Filed April 24, 1922 3 Sheets-Sheet l F49', 4

July 1 1924. 1,499,719

METHOD oF AND APPARATUS EUR usE TN THE MANUFACTURE L. BILL OF PIPES,TUBES, AND THE LIKE 3 Sheets-Sheet 2 Filed April 24, 1922 11m/exaltan L.l? 1'/ I/'l/e,

(Bj ibby.

July 1, 1924. 1,499,719

L. BILL METHOD OF AND APPARATUS FUR USE IN THE MANUFACTURE OF' PIPES,TUBES, AND THE LIKE Filed April 24 1922 3 Sheets-Sheet 3 I 121/ @zumPatented Jualy 1, 1924.

UNITED STATES PATENT OFFICE.

:LoN BILL, or NOGENT-summum, FRANCE.

METHOD OF AND APPARATUS FOR USE IN THE MANUFACTURE F PIPES, TUBES,

AND THE LIKE.

Application 'med .rpm 24, 1922. seran No. 556,281.

To all whom t may G01/wem.

Be it known that I, LON BILL, engineer, citizen of the French Republic,residlng at Nogent-sur-Marne, Department of the Seine, in France, andhaving P. O. address 37 Grande Rue, in the said city, have inventedcertain new and us'eful Improved Methods of and Apparatus for Use in theManufacture of Pipes, Tubes, and the like; and I do hereby declare thefollowing to be a full, clear, and. exact description of the invention,such as will enable others skilled in the artv to which it lappertainsto make and use the same.

This invention has for its subject matter a method of making pipes,tubes and the like of asphalt and reinforced cement, said cement beingin some cases obtained by melting.

The invention is clearly illustrated in the Aaccompanying drawings, inwhich Fig. l is a transverse sectional view of one form of tubeconstructed in accordance with the improved method,

Fig. 2 is a fragmentary transverse sectional vieW illustrating the stepsof applying and rolling the outer layer of asphalt,

Fig. 3 is a fragmentary elevational view of a mandrel with gagingrollers thereon,

Fig. 4 is a transverse sectional view of a modified form of pipe in theprocess.

Fig. 5 is an elevational detail of one section of a sectional mouldforming a pipe in accordance with the improved process,

Fig. 6 is a transverse sectional view through a sectional pipe in thecourse of constructlon,

Fig. 7 is a fragmentary longitudinal sectional view partly in elevationof the same 40 form,

Fig. 8 is a top plan detail of a wire winding mechanism,

Fig. 9 is a longitudinal sectional view of an improved pipe section,

Fig 10 is a transverse `sectional detail of a longitudinally disposedreinforcing rod,

Fig. 11 is a plan detail thereof,

Fig. 12 is an elevational view partly in section of the apparatus forcarrying out the improved method forming the pipe construction shown inFig. 1, and

Fig. 13 is a transverse sectional view thereof.

A tube, Figure vJ1, of asphalt, bitumen or other analogous material isfirst formed round an extensible mandrel or core 1, or roundl a lightconical tube l either by dipping the mandrel or core previously coveredwith a sheet of paper impregnated or saturated with asphalt, bitumen,shale-oil, tar, etc., in hot molten asphalt, or by pouring, applying orspreading one or more thany one layer of molten asphalt on or round thesaid mandrel or core, or by rolling the mandrel or core on a layer ofasphalt previously spread on a platform heated to a suitable temperatureby steam, hot water, gas burners or by any other suitable means. Onrolling the mandrel or core on the asphalt the latter adheres to thesaid mandrel or core and the joint may be smoothed over or made good bymeans of a hot iron with or without the use of asphalt. A preliminary orrst layer 4or thickness of molten asphalt mastic containing limestone,sand, etc., may be poured or spread on the mandrel or core; or apreliminary or first layer of hot powdered asphalt or a 4first orpreliminary layer of hot asphaltic concrete composed of small fragmentsor pieces of porphyry, ilnt, etc., sand and asphalt. The powderedasphalt or the concrete is. rammed and smoothed by means of suitable hotor cold tools in order to obtain the desired thickness. This rst layerof powdered asphalt or asphaltic concrete adheres only very slightly tothe pape-r or to the isolating material placed on the mandrel or core.According to the proportion of asphalt in the mixture, the isolatingmaterial may be dispensed with. A second layer of asphalt richer inbitumen is subsequently applied on the irst layer, the whole is thensubject to rolling or is rolled if so desired on a platform 8, Figure 3,which if desired maybe heated, the thickness being gauged by means ofrings 9 of suitable form which rings are mounted on the ends of themandrel or core.

` `BEISSUED If so desired a single water tight layer of asphalt may beused. The rolling may be replaced by a smoothing or fairing action bymeans of a suitable tool or tools which may'be hot or cold. Any suitablenumber of iron or steel bars or rods 3 are placed at suitable intervalsapart round the asphalt tube 2, Figure 1, these bars or rods beingarranged parallel to the axis of the tube. For this purpose the bars orrods have been previously engaged in loops or yeyes suitably spacedapart on small transversely arranged iron wires. By subsequentlyattaching or connecting the ends of the wires extending round the tubes,the bars or rods may be positioned round the said tube by a singlemovement. These longitudinal bars or rods form the framework or skeletonof the tube during construction. The asphalt tube fitted with these barsor rods is then rolled on a heated latform on which is spread a layer ofard stone fragments such as flint, porphyry, quartz or corundum, lava.or quarry-stone, coke; scoria or clinker, etc. 4, Figure 1. Thesematerials previously heated may be spread and applied on the tube eitherby handfor by means of the apparatus illustrated in Figures 12 and 13.The gravel or pieces of stone thus heated partly penetrate into theexterior of the asphalt tube 2 between the longitudinal steel bars orrods and adhere strongly to the asphalt after cooling, and as care hasbeen taken to add an additional ring 9, Figure 3, to the end of themandrel or core so as to increase the thickness of gauge, or to replacethe ringor rings which has or have already served as a gauge for thethickness of the asphalt, by other rings adapted to give the desiredthickness, a tube of asphalt containing gravel or stones may thus beformed by rolling, the exterior surface of the tube being of a perfectlycylindrical form. Cooling is now effected by ,W atering. The thicknessgauging rings are now changed or a different thickness of rings 9 isadded and the tube is placed on two cradles each comprisingtwo rollers12, Figure 4, with or without ball bearings, the thickness gauging ringsfor the tube bearing on these rollers. The rings 9 for this purpose maybe provided with a peripherally extending groove or recess 10, Figure 3,in which the rollers engage. The tube is then turned by hand with acrank' ory a hand wheel. o'r mechanically as shown in Figure 8, and aniron or steel wire 5 is wound thereon from above, the section and thedistance apart of the turns or convolutions of the wire being determinedso as to' resist the interior pressure which the tube will have tosupport.

After winding of the steel or iron wire 5, a first layer of pure cementor of thin cement mortar, that is to say, of a very fluid consistency,is applied on the tube, or by immersion of the tube in a bath of purecement or of very fluid cement mortar. The tube now somewhat moist isthen rolled on a platform provided with a layer of' cement mixed drywith sand or on a layer of 'cement mortar 6 mixed to a very firmconsistency. The cement mortar adheres to the turns or convolutions ofthe helically wound steel or iron wire and to the gravel or small stonesor pebbles and penetrates into the insterstices and the empty spaces ofthe material right up to the layer of asphalt. The thickness of thelayer of mortar and the almost perfect exterior cylindricity of the tubeor strictly' determined by the gauging rings. The mortar for a shorttime is allowed to set, then the rings 9 are removed and the mandrel orthe tube 1 which has served as a core is withdrawn. The interior layerof asphalt hardens or sets very quickly by cooling while the stones arewatered an the casing is rolled in cement mortar'. The removal ofthemandrel or core can be effected very quickly. The layer of cement mortarmay also be previously spread on a rubberised sheet, or on a piece oflinoleum or on a sheet 7, Figure 2, of any suitable flexible materialand by rolling the tube provided with stones or gravel and Wire windingson the said layer of cement mortar the sheet 7 guides the cement mortarand facilitates the adherence thereof round the tube. The aforesaidsheet is withdrawn as soon as the mortar becomes selfadherent to thetube. The tube provided with stones or gravel and wire winding may againbe enveloped with the aforesaid sheet and rolled on the platform 8 or itmay be subjected to the rolling action of a cylinder 13, Figure 4.

Instead of directly placing the longitudinal steel bars or rods 3 on theasphalt tube, before positioning or laying the gravel or stones 4, theVasphalt tube with the mandrel or core provided with suitable thicknessgauging rings, may be rolled on a heated platform having spread thereona layer of gravel or stones; or again, whilst the mandrel or core issupported through the thickness gauging rings on the rollers 12, Figure4, theV gravel or stones in a hot condition may be spread on or appliedto the asphalt tube either by hand or with the apparatus shown inFigures 12 and 13. The heat thereof partly melts the asphalt so that thegravel or stones become embedded or sink into the asphalt and theyadhere strongly thereto on cooling. The mass is then watered and apreliminary or first layer of cement mortar 11, Figure 4, is applied onthe gravel or stones and the cement mortar is caused to penetrate intothe spaces between the gravel particles and the stones right up to thelayer of asphalt. The layer of mortar is now rolled on a platform ortable or the said layer of mortar is subjected to rolling by the roller13, Figure 4, or by the apparatus shown in Figures 12 and 13 so as tomake the layer uniform. Then the longitudinal bars or rods 3 formingtheskeleton or framework previously attached at suitable distances apart tothe transverse iron wires are placed in position and the said wires arethen disposed round the pipe. A new layer of cement mortar of a veryfirm consistency is applied between the bars or rods 3, which layer maybe rolled or subjected to rolling. If necessary, this layer of mortar isallowed to set then the steel wire 5 is wound thereon by hand ormechanically, the convolutions or turns of the helically wound wireforming the constructive guide ribs or equivalent of the pipe.

Another layer 6 of mortar cement is subsequently applied either byrolling or otherwise as by hand. A further number of bars or rods suchas 3 may obviously be placed in position thereon then a layer 6 ofcement mortar, and then a further layer of wire winding which may becovered with a layer of cement mortar and this may be rolled orsubjected to rolling so that the tube may be continuously reinforced inthis manner with bars or rods 3 and helically wound wire, successivelyencased in a layer of cement mortar in order to impart the desired ornecessary resistance to the tube. Additional or further layers ofasphalt and gravel may if so desired be interposed between the layers Yof reinforced cement,

During these various operations, the thickness gauging rings 9 arechanged to meet requirements or new rings are added thereto in orderthat the roller 13 (or the platform ory table 8) rolling on these ringsmay'carefully gauge the thickness of the ,different layer of cementmortar and thus ensure perfect cen tering of the helically disposedwires or constructive guide ribs of the pipe as well as the almostperfect cylindricity of the exterior surface of the finished pipe ortube. rlhe apparatus shown in Figures 12 and 13 may be used for theapplication of the hot gravel and cement mortar. The mandrel or core iswithdrawn as soon as the pipe or tube has set suciently to preventradial distortion thereof, that is to say, sufficiently hard to preventthe tube or pipe becoming oval in 'stead of remaining cylindrical.

If desired use may be made of a brush heated by electricity or othersuitable means which maintains the asphalt in a hot condition during thespreading operation. This spread may be used to spread the single layerof pure asphalt or an asphalt rich in bitumen on the mandrel where onelayer only of asphalt is used; or the said brush may be used to spreadthe second layer of asphalt on the first thickness of powdered asphaltor of asphalticiconcrete in the case where the tube is formed of severallayers.

In order that the longitudinal bars or rods forming the skeleton orframework or constructive ribs of the pipe or tube may be readily andquickly placed in position round the asphalt core with or without gravelandV cement mortar the following arrangement may be used. The ends ofbars 45 of a suitable diameter are secured in and along the lengthof abeam 44, Figure 10, the said bars being spaced the same distance apartas the guide ribs when subsequently placed round the pipe or tube. Awire 46 of soft iron or mild steel is passed round the ends of the barsso as to'form a loop or eye 47 round each bar. The wires 46 arewithdrawn and they are then threaded or slipped onto the bars 48 whichform the constructive ribs of the pipe or tube, Figure 11. A metallicframe shown partly in Figure 11 is thus obtained which frame in onepiece is placed round the core. A metallic sheet, Figure 11, can thus beobtained by.placing the parallel bars in holes or slots suitably spacedapart according to requirements land engaging the loops or eyes 47directly with the bars. By joining and attaching the ends of the wires46, it will be possible to secure all the bars or constructive ribsround the core at 'one movement.

Instead of making the interior asphalt tube provided withgravel orstones in one piece and longitudinal bars encased in cement mortar, thefollowing method may be adopted more especially for pipes or tubes oflarge diameters.

A sheet of paper impregnated or saturated with asphalt, bitumen,shale-oil, tar, etc., is placed in moulds or formers 14, Figure 5,disposed horizontally, the curvature of the said moulds or formerscorresponding to the #curvature of the pipe or tube to be formed. Afirst layer 2 of Aasphalt mastic, or else hot calcareous asphalt crushedor broken is applied and rammed,

-Or asphaltic concrete made hot either bv gle watertight layer ofasphalt mastic may Y be applied. This is smoothed with a suitably curvedwooden or iron tool 16, Figure 5, cold or heated electrically or by anyother suitable means; which tool is attached to a curved/board 15,Figure 5, capable of sliding on the edges of the mould or former 14. Thethickness of the tool 16 is such as t0 givea uniform thickness to theasphalt 2. The layer 2 of asphalt may be readily and simply smoothedwith a tool of wood or hot or cold iron. A layer of gravel (or hotstones) is subsequently spread. on the asphalt, the gravel (or hotstones) penetrating into the asphalt. The mass is watered andaJ thinlayer 17 of cement Vmortar is applied which fills up the spaces betweenthe particles or stones right up to the layer of asphalt. The thicknessof this layer of cement mortar is gauged by means of a depth piece 16attached to the curved member or board 15, Figure 5. On the cementmortar is placed a number of iron or steel bars 3, Figure 5, which form,the framework or constructive ribs of the pipe or tube to be formed.These bars are placed in the loops or eyes 47 of the transverse wires46, which maintain them at suitable distances apart, Figure 11.- Themould or former is then filled with cement mortar 18 .the thickness ofwhich is carefully gauged by the curved member 15 slidably mounted onthe edges of the mould or former. The cast is removed from the mould orformer after setting. Arcuate segments or elements of the tube are thusobtained which are temporarily mounted and attached on two ordinary oreXtensible wheels 19, Figures 6 and 7, which are mounted on a rotatableshaft 21 supported on uprights 22, either in the factory or works or insitu at the place where the tubes or pipes are required.

Where the construction of the pipes or tubes requires theuse of a trenchtheuprights 22 are much shorter than a radius of the pipe or tube sothat one of the uprights may be supported in t-he interior of a part ofthe finished tube preceding the tube to be subsequently constructed, andthe second upright would then be supported onk a suitable temporarybracket, block or equivalent.

The two wheels are provided with end rings .or end discs 20, Figure 7 bywhich the thickness can be gauged. The asphalt mastic is run in, or thepowdered asphalt or the hot asphaltic concrete 23 is rammed in betweenthe layer of asphalt or asphaltic concrete of two consecutive segmentsor elements by placing a board or equivalent unstones 24, Figure 6, anda layer of cement mortar 26 is applied on the layer 24 of gravel or hotstones, Figure 6, a bar 25 of steel or iron"`being embedded therein ifso desired. The joint of cement is made flush by means of a board orequivalent with the exterior surface of the arcuate segments or elementsof the pipe or tube. The various operations of the longitudinal jointsbetween the arcuate segments or elements are always effected above thetube or pipe andk the wheels 19 are turned gradually as required. Thetube thus formed by the assembly of the arcuate segments or elements iswound with iron or steel wire 5, Figure 7, the section and pitch of theturns or couvolutions of the wire being previously determined so as togive the desired resistance to the pipe or tube. The aforesaid helicalwire winding may be eiiected by hand or mechanically as indicated inFigure 8. The tube or pipe is inishedby the applicationy thereto of alayer of cement mortar 6 which may be subjected to a rolling action bythe cylinder 13 or by the apparatus,Figures 12 and 13, rolling orturning on the thickness gauging'rings 20. The arcuate segments orelements may be of any suitable or desired number. Another series oflongitudinal bars or constructive ribs and helicallyy arranged wires maybe superposed round the pipe or tube with as many layers of cement asdesired, the thickness of the gauging lrings being gradually; changed tomeet requirements orY new rlngs being added as found most convenient;changing of the thickness gauging rings may be avoided by the usefofvthe apparatusshown in Figures 12 and 13 which permits of the severallayers of helical wire and layers of cement being perfectly concentric.Further layers 'of asphalt may be interposed between the layers ofreinforced cement. Y

When the tube or pipe is inished and the cement has setk suiicientlyhard the said tube or pipe is shored up from below so as to wedge it inplace. The spindle or shaft 21 then withdrawn likewise the thicknessgauging rings 20 one of which escapes or` falls oil by reason of theplay' allowed for the expansion of the joint between the preceding pipeor tube and the pipe or tube which has just been finished. Theextensible -wheels 19 are then removed and finally the uprights ortrestle support. All these operations can be effected at the bottom of ahollow or dug-out trench the depth of which is suicient to allow thepipe or tube to be turned.

The cement mortar can also be applied,

round the tube or pipe formed by the arcuate Vsegments or elementsassembled round the wheels 19 where the manufacture is efected outsideof the trench, by rolling it on a platform provided with cement mortar-with or without the aid of the sheet'7, Figlao Wards and the stony sideoutside and the joints are united either bya cover joint of asphaltcoated with cold soluble asphalt, or with molten asphalt which may besmoothed over with a suitable hot or cold tool. Sheets of macadamizedasphalt may be used for the interior layer of asphalt in the manufactureof arcuate segments or elements for tubes or pipes of large diameters.The sheets of asphalt may even be prepared in advance with or withoutreinforcements, macadamize them hot on one side and bend or shape themon the mandrel or mould them and join them at the junction ashereinbefore described. In certain special cases the asphalt masticV aswell as the cement mortar may have incorporated therein pumice stone orpowder or other light material in place of sand, so as to produce alighter pi e or tube.

igure. 8 shows the method of mechanically winding the steel wire on thetubes or pipes 27 vin accordance with the method hereinbefore described.On the thickness gauging ring 9 or 20 is secured a toothed wheel or apulley 28. A screw-threaded shaft 31 carries a pinion 29 actuated by achain or a belt 30 passing round the wheel 28. A coil or reel 36 ofsteel wire is placed on a platform or table 60 provided with a spindleor shaft 36. A brake 61 is employed to modify the s eed of the platformor table 60. The wire 37 passes between the jaws of a vice 38 by meansof which the desired tension can be given to the wire, This vice isfixed on a carriage sliding along the screw 31. This vice 38 is ided ontwo parallel bars or rods 39 and 40. A toothed wheel or pulley 32 iskeyed on the other thickness gauging ring, which wheel or` pulley isconnected by a chain or belt 33 to a ypinion 34 keyed on the motorshaft'35 or other suitable power transmission device. The motor drivesthe v tube 27 the other wheel 28 of which effects the rotation of thescrewed spindle 31. The latter in its rotation causes the automaticadvance of the carriage 50 and the vice 38 carried thereon durin thewinding of the wire 37 on the tube 2 helical coil, the distance apart orthe pitch of the convolutions'or turns of the helical coil beingdetermined by the speed in conjunction with the pitch of the threads onthe screw-threaded spindle 31. A change speed gear box analogous to thatof parallel or slides lathes may be adapted for use with the aforesaidarrangement for winding the wire, so as to obtain the usual speeds andpitches by the simple manipulation of levers.

Whatever may be the method of manu/facture of the tubes or pipeshereinbefore described when these are finished, and the cement mortarhas completely set, very hot asphalt or a solution of cold asphalt isapplied to the extremities 42 and the ends 43,

or a sheet of smooth asphalt is carefully consolidated with `the asphalt2 of the interior the interior, the extremities and the ends of l thetubes. ,v

Figures 12 and 13 show the apparatus for the mechanical application ofthe hot gravel and the various layers of cement on the asphalt tube andreinforced cement previously described. j

The thic s gauge rings 70 are each formed or provided with a recess 71with which the rollers 72 engage. The` rollers 72 are supported inbearing blocks darried on blocks 73 which are secured on a platform ortable 74. -Handles 75 of any suitable number are screw-threaded into theouter side of a disc 7 G rigidly secured to the gauging rings 70 and bymeans of the handles, the rings -70 and the extensible mandrel 77rotated thereby can be slowly turned 'by hand or by a lever.

When the whole of the apparatus 79 is in Iplace the rollers 80 engage inthe recesses 1 in the gauging rings. These rollers have a plain edgewhen the thickness gauging rings are provided with a slot. The saidrollers are provided with a groove when they are intended for use withthe thickness gauging discs 20 or the like, the ridge side of the rollerbeing disposed against the rim of the disc when provided for use in themanufacture of tubes with arch-like segments or elements of asphalt andreinforced cement.

vThe apparatus is maintained against the thickness gauging rings bysprings 100 secured to the upper ends of the supports 82.

The-lower part of the apparatus 79 is further supported on the table 81provided with a stop 101. The apparatus is formed by two sheet metalsupports 82, Figure 12, in which are fixed the spindles 83 of therollers 80. into the form of a A cross beam 84 connects the two supportsby means of angle irons or by means of a shaft 85. On this beam isplaced a sheet of metal or a plate 86 with two slits 87 by means ofwhich the desired distance of the smoothing board can be controlled asde# sired by screws 88, Figure l2, which permit of the smoothing boardbeing displaced into any desired position.

Another cross beam 89 is secured likewise between the two supports 82"by the same means as the beam 84. On this cross beam 89 is placed asheet of metal or a plate 90 having two openings which permit of thedisplacement or the adjustment of the smoothing board to the desiredposition by the aid of screws.

Above the two plates suitably adjusting screws may be provided and theinclination of the U-shaped cross beam which carries them may also beadjustable.

Below the aforesaid cross beams a 'screw 92 ported at each side in theends of the screws 92.

The action of the apparatus is as follows:

For the application of hot gravel, this gravel is run in front of theplate 86 which is adjusted to a suitable distance and while turning themandrel and the tube the gravel abuts against the rolling cylinder 97adjusted to a suitable distance in such manner that all the particles ofthe gravel or of the stones are rolled and have their exterior face at auniform distance from the axis of the tube or pipe.

For the application of cement mortar, this cement mortar 98 is run inbetween the formed tube 78 and the plate 86 which is adjusted to anydesired distance. This plate 86 forms a trowel throughout the length ofthe tube and by turning the mandrel the cement mortar is applied to thetube throughout its length to the desired thickness. The plate 90adjusted to a suitable distance removes the excess of cement mortar andthe cylinder 97 adjusted also to a suit able distance packs the cementmortar and vrenders the surface extremely uniform or homogeneous. Allthe operations are effected very rapidly throu hout the length of thetube or pipe while t e latter is slowly rotated on the rollers 72.

This method of manufacture of 'tubes presents many advantages' which may.be summed up as follows: Perfect fluid tightness under the highestpressures due to the interior asphalt wall as well as the asphaltapplied Von the extremities and the ends;

extreme resistance due to the exterior wall of reinforced cement;perfect adhesion between the asphaltwalls and the reinforced cement;possibility of making tubes of all diameters anywhere even at the bottomof trenches which avoids the cost of transport and the handling of thetubes; suppression of binding material between the metallic skeleton orframework and the convolutions or turns of the helically wound wirewhich forms the constructive ribs of the tubes; perfect centering of theconvolutions or turns of the helically wound wire; great uniformity ofthe tubes ensured by the thickness gauging rings; great resistance towear and tear due to the grains of sand, limestone or pieces of hardstone incorporated in the asphalt mastic or the asphaltic concreteforming a covering analogous to that of tion what is claimed as new anddesired to be secured by Letters Patent is l. The method of forming aconcrete pipe' consisting of applying a layer of asphalt about the core,arranging a metallic reinforcement about the layer, embedding mineralaggregate between the reinforcement and into the layer, wrapping a Awireabout the aggregate and reinforcement to retain the same, then dippingthe product in a cementitious solution to bind the wrappingreinforcement mineral aggregate and layer, and finally applying a layerof solid cementitious material about the binding.

2. The method of making reinforced concrete pipes consisting in applyinga layer of asphalt about a core, arranging a series of interconnectedrods about the layer and parallel with the axis of the core, embeddinmineral aggregate between the rods an about the 'asphalt layer, wrappinga wire about the mineral aggregate and rods so as to retain the same,then dipping the article in a solution of cementitious material to bindthe wrapping mineral aggregate and rods with the first layer, applying alayer Aof solid reinforcement cementitious material about the bindingand finally smoothing the outer layer.

3. A method as claimed in claim 2 including the step of temporarilyapplying gauging rings to the ends of the core to insure. of theproduction of a smooth even surface on the first asphalt layer.

4. A method as claimed in claim 1 including the step of applying anisolating material about the core.

5. The .method offorming concrete pipes consisting in applying anisolating material about a core, rolling the core through moltenasphalt, applying reinforcing rods about the asphalt layer, rolling thecore over mineral aggregate to embed the same in the asphalt layer,rotating the core and simultaneously wrapping a wire about the aggregateand rods, dipping the core into a bath of molten asphalt so as to bindthe wire aggregate and innerlayer together and finally applying a layerof solid cementitious material about described method, comprising aspaced pairs of rotatable rollers t ereon, a core, a pair of gaugingrings having recesses for engagement with the rollers on the plat- 5form, a secondary support, a trowel, a smoothing board, means foradjustably mounting the troWel and the smoothing board on the support,supporting rollers on latform, n

the secondary support for engaging the re-- cesses inthe gauging rings,and a packing 10 roller rearwardly of the smoothing board, as and forthe purposes set forth.

In testimony whereof I have signed my name to this specification.

LEON Y BILLE.

